Arsenal beware: on Leyton Orient's challenging pitch, Stephen Dawson and his crew plan to rough up the Premier League aristocrats when they walk out at the Matchroom Stadium for the FA Cup fifth-round tie this afternoon.

"I don't think it will be like the Emirates, it's not the flattest you'll ever see," says Dawson, the Orient captain, of a surface that had to be completely relaid in 2008. "It will help us. They've got the Carling Cup final next week and Barcelona at the Camp Nou [in the Champions League next month], they don't want to be doing a 50-50 challenge at Brisbane Road.

"We're not just going to stand around and admire how they play. Whoever I mark, be it Cesc Fábregas or Alexandre Song or Jack Wilshere, whoever they put out, you want to put one over on them and beat them. That's the main thing. Whether it involves a tackle or not, that's part of football isn't it?

"Against Ipswich [in the Carling Cup] and Huddersfield and Leeds [in the FA Cup] Arsenal got put under pressure and I don't think they really liked it. It's not about kicking them around, it's about getting in their faces – we're going to be right on top of them."

Arsène Wenger's team travel across London with extra zip after Wednesday evening's memorable 2-1 Champions League comeback win over Barcelona. Yet Irishman Dawson, 25, only sees the potential advantage in taking on a team who are also second in the Premier League and still chasing an unlikely quadruple.

Two years ago, the midfielder was relegated to the Conference with Mansfield Town before being released, so his rosy view of life now is understandable. He says: "I know they are professionals [but] there are an awful lot of internationals who might have the mentality, 'OK, let's just get through the game'."

Helping Dawson and his colleagues in their quest to pull off one of the great FA Cup shocks will be 70 or so of his family and friends, plus a factory full of Cadbury employees in his native Dublin, where his father, Brendan, works.

"He worked 15 hours a day for the last 20-odd years and brought us up very well. I shouldn't say this, but my Mum would have one or two drinks in the pub and my dad would have to look after us, so he would give us a football.

"To say he's proud about this game is an understatement. He'd been a window fitter, but he's working for Cadbury now and has probably got around 3,000 workers there all watching the game as well. More Cadbury people will be Leyton Orient fans on Sunday. More than the usual Tuesday night crowd in the stadium."

Orient pull in around 4,500 for home games and, this season, they have seen their club, owned by Barry Hearn, go on a run that has featured the attractive football favoured by Russell Slade, the manager. They have lost only once in 20 games and have moved up the League One table to be within three points of the play‑off positions.

This sequence featured an FA Cup second-round replay against Droylsden that the club website correctly described as "one of the most bizarre [games] you'll ever see". Dawson says: "There was about eight minutes left, with us 2-0 down – and with 10 men as well. But we managed to get two goals and it ended 8-2 [in extra time, with both teams reduced to nine men by the finish]. They were thinking: 'What's going on here?' It was one of those games."

Dagenham, Norwich and Swansea are the three other scalps taken by Orient in their FA Cup run, but making Arsenal number five appears particularly unlikely. Even if Wenger rests one or all of Fábregas, Samir Nasri, Robin van Persie, Theo Walcott and Wilshere, a stellar queue of reserves, headed by Andrey Arshavin, Tomas Rosicky and Nicklas Bendtner, can step in.

Dawson's hero when he was growing up in Dublin was Roy Keane and he recalls the Manchester United captain's tussle with Patrick Vieira at Highbury in February 2005. "Vieira picked on [Gary] Neville and Keane, who was a foot shorter than Vieira, had a go at him. That's what I grew up on," he says. "Roy Keane is an absolute idol. I managed to train with the Irish team and I wasn't scared of that, I was scared of meeting Roy. He shook my hand, but if you gave away the ball he'd go mad at you."

Whatever the result, those travelling friends and family face a short trip to Dawson's post-game party. "I live in the corner flat that overlooks the ground, you can see the pitch up to the penalty spot," he says of the property owned by Hearn. "There'll be a few drinks."

There could be more in Nevada. Leyton Orient's best FA Cup run was in 1978, when they reached the semi-finals, at which point Sunday's opponents beat them 3-0 at Stamford Bridge. But if they manage even a draw against Arsenal, Hearn has promised to take Dawson and his team‑mates to Las Vegas for a celebration to remember.